The complex social system of mole rats, in which members cooperate to raise the dominant breeding pair’s offspring, is often regarded as a unique mammalian equivalent of the colonies of ants, bees and other eusocial insects. But new research suggests they differ in a crucial respect.
Many social insects operate a caste system, in which each individual is specialised to perform a particular task in the colony – nest maintenance, foraging or defence, for example.
“Social mole rats were thought to be unique among vertebrates, in that they also had castes,” said Markus Zöttl of the University of Cambridge.
But, by recording the behaviour of hundreds of individual Damaraland mole rats over three years in the Kalahari, Zöttl and his colleagues have shown that mole rats are generalists rather than specialists.
The only differences were age related – older animals perform a greater range of tasks than younger ones.
“Mole rat social organisation probably has more in common with the societies of other cooperative mammals, such as meerkats and wild dogs, than with those of social insects,” explained Zöttl.
Main image: Damaraland mole rats (pictured here) and naked mole rats are the only eusocial mammals known to science. © pilipenkoD